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Chapter 4 - Reviewing Previous Data

This chapter takes you through the procedure of reviewing previous data. The review of previous data allows you to re-analyse and re-graph the data, changing analysis parameters and graph parameters as required. It is not necessary to have a JCI155v4 Instrument connected in order to review previous data.

Reviewing previous data immediately throws up the problem of finding the data to review. A later chapter shows how your data can be stored in a hierarchical directory (category) system derived from the MS-DOS® filing system, to simplify the location of data.

Starting &Running the program

Turn on the computer and allow to boot up. Insert a floppy disc on which data has been stored from one or more charge decay runs, for example the floppy disc used for "Getting started with a paper sample". Then follow the steps in chapter 2 up to the point when the main menu first appears.

If selection 2 of the main menu (figure 2.1) is anything other than the standard selection reading "Access to data directories", turn to Chapter 13 ("Trouble shooting" §Disc Drive Problems). Choosing selection 2 leads to a "File / Directory Picker" screen, figure 4.1 below.

Figure 4.1 - File / Directory Picker screen (Current Directory selected)

Selecting a previous run from among other data

This screen is designed to allow you to select files from directories without typing file names. One item is highlit. On entry to this screen, this is normally *CURRENTDIR* in the Directories Panel as shown above. To select an item in another panel, e.g. the file AD200205.07D in the Data File Panel follow the instruction in the top right hand corner of the required panel (repeating if necessary) until the highlit selector arrives in that panel. The instruction will now change to indicate the arrow and other keys that can be used to highlight and thus select the required file from this panel.

Figure 4.2 - File / Directory Picker screen (Data File selected)

Naming of files

The first indication you have of which file to select is the date and time of the file, which are embedded in the file name. The digits in the file name example above indicate that it was stored at 20:02 hrs on the 5th day of the 7th month of the current year. If more than one file was stored in that minute, the starting letters run in sequence from A upward. Note also that if this picker is entered immediately after a data collection run, the highlit selection will be on the file stored as a result of that run. The files appear in the Data File window in order of filing, along rows.

The highlit file you require to review may be loaded as indicated on the return key instruction, bottom right, by pressing. The picker screen will then be replaced by a loading message, and eventually by the Analysis Preparation Menu, Figure 4.3. below. If some problem prevents this, please see Chapter 13 ("Trouble shooting" §Disc Drive Problems).

Figure 4.3 Analysis Preparation Menu Screen

Selection of Analysis Parameters

When reviewing previous charge decay data or immediately after a charge decay run, certain of the analysis parameters are set by default to correspond with analysis parameters suggested at the time of the charge decay run. These parameters are chosen automatically when selection 2 of the Analysis preparation menu is chosen. When the program was loaded, both the default and the current values of analysis parameters were set to identical values determined by a setup file. The current values, unaffected by the Charge Decay Data file loaded (or the latest charge decay run) can be accessed by selection 1 of the Analysis Preparation Menu, i.e. Analyse with Selectable Parameters.

Making this selection leads to the Analysis Parameters Menu, figure 4.4 shown below.

Figure 4.4 - Analysis Parameters Menu

Analysis Parameters Menu

The parameter values shown are the current values as loaded from a setup file, together with any changes you may have made. If the default values, as set by the last data file loaded for review, or the last run made, differ from the current values, they may be accessed:

The parameters

These are discussed briefly here, more fully in Chapter 5.

Of the above parameters, those superscripted ¹ will have default values affected by the last data file loaded / last charge decay run, while those superscripted ² will have their default values unaffected.

Proceeding from this menu causes the Analysis to be to be performed on the charge decay run, as described in Chapter 2. If a significant amount of averaging / spike suppression / zero shift have been applied, the analysis results may differ from the original run results. When the analysis is terminated, it is saved and then the Graph Preparation Menu is entered.

Selection of Graph Parameters

When reviewing previous charge decay data or immediately after a charge decay run, all default graph parameters are set by the analysis process, to fit the whole graph on screen and set the centre of the Local Time Constant Range so that there are approximately as many readings above as below. These default parameters are chosen automatically when selection 2 of the Graph Preparation Menu is chosen. When the program was loaded, both the default and the current values of graph parameters were set to identical values determined by a setup file. The current values, unaffected by the file loaded (or the latest charge decay run) can be accessed by selection 1 of the Graph Preparation Menu, i.e. Graph with Selectable Parameters[1].

Making this selection leads to the Graph Parameters (Display Axes) Menu shown below (figure 4.5).

Figure 4.5 - Graph Parameters Menu

Graph Parameters (Display Axes) Menu

The parameter values shown are the current values as loaded from a setup file, together with any changes you may have made. If the default values, as set by the last data file loaded for review, or the last run made, differ from the current values, they may be accessed

The parameters

These are discussed briefly here, more fully in Chapter 11.

These parameters are best adjusted after having viewed a charge decay graph using the default parameters, in order to improve the appearance of the graph, or focus on some point of interest. Alternatively they may be set to suitable values for displaying a whole set of graphs, so that when prints of the graphs are made they are to the same scale to facilitate comparison.


[1]  Note that this is useful for plotting multiple graphs to common axes for easy comparison. (See "The parameters", next page.



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